Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 140930
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
330 AM CST Tue Feb 14 2017

.SHORT TERM...(Today and tonight)
Issued at 330 AM CST Tue Feb 14 2017

Cold advection today and warm advection beginning tonight in the
west will highlight the short term period.

Currently, a strong upper level ridge over western North America
extended well into northwestern Canada and eastern Alaska with a well
established upper level low over Hudson Bay. This has resulted in a
northerly/northwesterly flow aloft over the Dakotas.

A shortwave in the upper level flow will move south/southeast across
the state this morning. An associated surface cold front will sweep
southeast across the state this morning as well, but mainly
affecting the eastern half of the state. The models depict cold
advection in the east this morning, with neutral temperature
advection this afternoon. Over western ND, neutral temp advection
this morning with warm advection from the west this afternoon as the
western upper level ridge builds eastward. Looking at highs today
only reaching the upper 20s in the Turtle Mountains, with the
southwest seeing lower 40s this afternoon.

Tonight as the western ridge continues building eastward, warm
advection aloft will expand eastward across the state. Look for low
temperatures in the mid to upper 20s in the west with teens in
eastern portions of central ND.

.LONG TERM...(Wednesday through Monday)
Issued at 330 AM CST Tue Feb 14 2017

The potential for record breaking temperatures Wednesday and
Thursday highlights the long term period.

The strong meridional upper level ridge expands/moves eastward into
the plains Wednesday and the apex of the ridge reaches the Dakotas
on Thursday.

As discussed in the forecast discussion from Monday afternoon,
the 00 UTC NAEFS ensemble mean depicts an anomalous upper level
ridge to build across the Northern Plains characterized by 500 mb
height anomalies in their 99th percentiles and a very warm low level
airmass with 850 mb mean temperature anomalies at their 99.5th
percentiles. 850 mb temperatures are forecast to reach 10C over the
western half of the state Wednesday, with +8C over the Turtle
Mountains and James Valley. On Thursday the 10C 850 mb temps are
forecast to reach the Turtle Mountains and James Valley with 12-14C
in the west.

With favorable westerly winds and increasing bare ground, especially
across the southwest and south central, record or record breaking
temperatures are forecast. This is well above even the warmest edge
of the forecast guidance envelope given the anomalous nature of the
event.

Location....Wed Record...Wed Forecast......Thu Record...Thu Forecast

Dickinson...53 1981.........55..............59 1981.......61
Williston...50 1998.........49..............54 1981.......54
Bismarck....59 1931.........48..............57 1981.......52
Minot.......54 1931.........46..............51 1913.......51
Jamestown...55 1931.........40..............52 1981.......46

The upper level ridge moves east Thursday night, and by Friday the
upper level flow over the Dakotas becomes southwesterly. An upper
level shortwave moves northeastward through the flow Friday, but the
lack of moisture accompanying it resulted in very low chances for
rain from the consensus model blends. Meanwhile the parent upper
level trough continues to develop over the west coast, with the
global model solutions lifting a more potent shortwave across the
plains late in the weekend. This will bring a chance of rain or snow
to our area beginning Sunday night. Temperatures are still forecast
to be above average, with highs in the 30s and 40s through Monday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1218 AM CST Tue Feb 14 2017

VFR conditions expected through the 06Z TAF period with a light to
moderate west to northwest surface flow.


&&

.HYDROLOGY...
Issued at 258 PM CST Mon Feb 13 2017

Unseasonably warm temperatures across the region will continue
this week and will speed the snow melt. Up to this point, the melt
rate has been very mild with water being trapped in the remaining
snow, or in the upper few inches of the ground. As warm
temperatures persist, pathways will open for meltwater to reach
streams and rivers, and levels will rise.

Overall, this early melt should be beneficial with helping
remove excess moisture from river basins in the southern and
western parts of North Dakota. Watersheds including the Knife,
Heart, and Cannonball Rivers should be on the watch for rising
water levels and an increased risk of ice related high water near
the end of the week. To a lesser extent, the Apple and Beaver
Creek basins may also see the onset of runoff this week as their
robust snowpack proves more resilient.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...JV
LONG TERM...JV
AVIATION...JV
HYDROLOGY...AYD



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